首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   547篇
  免费   43篇
电工技术   1篇
化学工业   66篇
金属工艺   50篇
机械仪表   3篇
建筑科学   14篇
矿业工程   1篇
能源动力   19篇
轻工业   165篇
水利工程   6篇
石油天然气   3篇
无线电   42篇
一般工业技术   46篇
冶金工业   88篇
原子能技术   1篇
自动化技术   85篇
  2022年   2篇
  2021年   6篇
  2020年   8篇
  2019年   8篇
  2018年   18篇
  2017年   13篇
  2016年   18篇
  2015年   17篇
  2014年   23篇
  2013年   27篇
  2012年   30篇
  2011年   52篇
  2010年   22篇
  2009年   23篇
  2008年   32篇
  2007年   43篇
  2006年   38篇
  2005年   36篇
  2004年   20篇
  2003年   15篇
  2002年   15篇
  2001年   9篇
  2000年   5篇
  1999年   7篇
  1998年   43篇
  1997年   20篇
  1996年   11篇
  1995年   8篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1981年   2篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
排序方式: 共有590条查询结果,搜索用时 15 毫秒
1.
2.
3.
Fungal β‐1,3‐glucan glucanosyltransferases are glucan‐remodeling enzymes that play important roles in cell wall integrity, and are essential for the viability of pathogenic fungi and yeasts. As such, they are considered possible drug targets, although inhibitors of this class of enzymes have not yet been reported. Herein we report a multidisciplinary approach based on a structure‐guided design using a highly conserved transglycosylase from Sacharomyces cerevisiae, that leads to carbohydrate derivatives with high affinity for Aspergillus fumigatus Gel4. We demonstrate by X‐ray crystallography that the compounds bind in the active site of Gas2/Gel4 and interact with the catalytic machinery. The topological analysis of noncovalent interactions demonstrates that the combination of a triazole with positively charged aromatic moieties are important for optimal interactions with Gas2/Gel4 through unusual pyridinium cation–π and face‐to‐face π–π interactions. The lead compound is capable of inhibiting AfGel4 with an IC50 value of 42 μm .  相似文献   
4.
A single‐chamber air‐cathode microbial fuel cell (MFC) was successfully applied for decolorization of the diazoic dye Reactive Black 5 (RB5) with simultaneous production of electricity. An innovative low‐cost medium, the marine water‐glucose‐yeast extract medium (MWGY), was developed which appears as a textile marine effluent in terms of salinity. The anode compartment containing a single bacterial strain of Stenotrophomonas sp. showed almost complete dye decolorization with different RB5 concentrations after seven days of treatment. For the four dye concentrations used, a correlation between dye removal and production of electrical energy was found. The comparison of the decolorization process in the MFC with that in a batch reactor as control experiment highlights the efficiency of the single‐chamber air‐cathode MFC technology which improved the dye removal by the same bacterial strain.  相似文献   
5.
A series of peptide nucleic acid–oligo(bicycloguanidinium) (PNA–BGn) conjugates were synthesized and characterized in terms of cellular antisense activity by using the pLuc750HeLa cell splice correction assay. PNA–BG4 conjugates exhibited low micromolar antisense activity, and their cellular activity required the presence of a hydrophobic silyl terminal protecting group on the oligo(BG) ligand and a minimum of four guanidinium units. Surprisingly, a nonlinear dose–response with an activity threshold around 3–4 μM , indicative of large cooperativity, was observed. Supported by light scattering and electron microscopy analyses, we propose that the activity, and thus cellular delivery, of these lipo‐PNA–BG4 conjugates is dependent on self‐assembled nanoaggregates. Finally, cellular activity was enhanced by the presence of serum. Therefore we conclude that the lipo‐BG‐PNA conjugates exhibit an unexpected mechanism for cell delivery and are of interest for further in vivo studies.  相似文献   
6.
7.
Thirty-two lambs were finished on a total mixed ration (TMR) pelleted alone (00SS) or including sunflower soap stock (SS): 15SS (15 g SS per kg TMR), 30SS (30 g SS per kg TMR) and 60SS (60 g SS per kg TMR). Lambs (8 per group) were slaughtered at 27 kg live weight. Colour evolution, lipid oxidation, microbial growth and detection of diarrhoeagenic Escherichia coli were studied in meat samples. SS in the diet reduced meat lipid oxidation (< 0.05), but had no significant effect (P > 0.05) on the cholesterol oxidation products. Meat from 60SS and control animals (00SS) revealed greater discoloration (< 0.05) than 15SS. SS supplementation did not affect the microbiological populations, whereas high doses of SS seemed to increase the proliferation of diarrhoeagenic E. coli on day 14 (< 0.10). These results suggest that the rate of SS inclusion in the diet of fattening lambs should not be above 15 g SS per kg TMR.  相似文献   
8.
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号